6 month old VERY sleepy!

my son is just hitting 6 months. he has been falling asleep very early around 6PM and waking up at 6AM.

it’s now 12 in the afternoon and he’s napping for the third time today! and pretty much the entire time he was awake he was cranky.

if he’s awake he’s either chewing on something or wanting milk.

does this sound like a growth spurt? if not, what? (about the chewing, his bottom two teeth broke through already a few weeks ago.)